Wasps have described referee Mathieu Raynal's critical mistake in their defeat to Connacht as "hugely disappointing" but Pat Lam is refusing to let the issue cloud his side's win.

Raynal, who replaced injured official Jerome Garces late in the second half of the Sportsground clash, allowed an injury-time lineout to be taken after a penalty was kicked to touch when he should have advised Connacht captain John Muldoon that putting the ball out would result in the end of the game.

The Westerners scored from the set-piece and Jack Carty's conversion won them the game to level things up at the top of Pool 2, with Wasps, Toulouse and the Pro12 champions all on 13 points.

"We just ask the question and we got the answer," Lam said. "No, not at all (it hasn't taken from the win). We play what's in front of us.

"It is really nothing to do with us. We asked the question, we got the answer. If the ref said 'no, you can't kick the ball out', then we would tap it and we will go for the corner. That decision didn't win us the game."

Although Wasps won't challenge tournament organisers EPCR's decision to stand by the result, they are not happy with the French official.

"We all understand referees are only human and mistakes do occasionally happen," a statement read.

"However, for a referee and fourth official to get the laws of the game wrong at a crucial stage of a big match is hugely disappointing. The error made could have serious repercussions in terms of Wasps' qualification hopes or the prospect of securing a home quarter-final."

Meanwhile, Wasps coach Dai Young fears his club may struggle to hold on to Irish centre Brendan Macken, whose contract expires at the end of the season.

"He's a quality player and I've loved having him. We want to keep him, but I'm sure there comes a point where he's going to be really close to starting week in, week out for other teams," Young said.

"He's done everything that is asked of him with us and he's a quality player. We'll fight tooth and nail to try and keep him, but he's a starter in most teams."

The former Wales and Lions prop was loud in his praise of Marty Moore, who came off the bench in Saturday's defeat and had a real impact at the scrum.

"Marty's been excellent. He struggled at the start of the season just to put games together. He had little injuries, he never quite got a run," said Young. "He's really starting to show what we knew he had.

"His mobility around the field, he hits a hell of a lot of rucks, makes a lot of tackles and secures a lot of ball. We've talked to him about being much more of a dominant ball carrier, which he's bringing to his game. His ball carrying is part of his game we believe he's improved.

"He has scrummaged well and (on Saturday) he helped take our scrum to another level."